import hashlib
import os

import chardet
import requests

from changedetectionio.content_fetchers.exceptions import BrowserStepsInUnsupportedFetcher, EmptyReply, Non200ErrorCodeReceived
from changedetectionio.content_fetchers.base import Fetcher


# "html_requests" is listed as the default fetcher in store.py!
class fetcher(Fetcher):
    fetcher_description = "Basic fast Plaintext/HTTP Client"

    def __init__(self, proxy_override=None, custom_browser_connection_url=None):
        super().__init__()
        self.proxy_override = proxy_override
        # browser_connection_url is none because its always 'launched locally'

    def run(self,
            url,
            timeout,
            request_headers,
            request_body,
            request_method,
            ignore_status_codes=False,
            current_include_filters=None,
            is_binary=False):

        if self.browser_steps_get_valid_steps():
            raise BrowserStepsInUnsupportedFetcher(url=url)

        # Make requests use a more modern looking user-agent
        if not {k.lower(): v for k, v in request_headers.items()}.get('user-agent', None):
            request_headers['User-Agent'] = os.getenv("DEFAULT_SETTINGS_HEADERS_USERAGENT",
                                                      'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.66 Safari/537.36')

        proxies = {}

        # Allows override the proxy on a per-request basis

        # https://requests.readthedocs.io/en/latest/user/advanced/#socks
        # Should also work with `socks5://user:pass@host:port` type syntax.

        if self.proxy_override:
            proxies = {'http': self.proxy_override, 'https': self.proxy_override, 'ftp': self.proxy_override}
        else:
            if self.system_http_proxy:
                proxies['http'] = self.system_http_proxy
            if self.system_https_proxy:
                proxies['https'] = self.system_https_proxy

        r = requests.request(method=request_method,
                             data=request_body,
                             url=url,
                             headers=request_headers,
                             timeout=timeout,
                             proxies=proxies,
                             verify=False)

        # If the response did not tell us what encoding format to expect, Then use chardet to override what `requests` thinks.
        # For example - some sites don't tell us it's utf-8, but return utf-8 content
        # This seems to not occur when using webdriver/selenium, it seems to detect the text encoding more reliably.
        # https://github.com/psf/requests/issues/1604 good info about requests encoding detection
        if not is_binary:
            # Don't run this for PDF (and requests identified as binary) takes a _long_ time
            if not r.headers.get('content-type') or not 'charset=' in r.headers.get('content-type'):
                encoding = chardet.detect(r.content)['encoding']
                if encoding:
                    r.encoding = encoding

        self.headers = r.headers

        if not r.content or not len(r.content):
            raise EmptyReply(url=url, status_code=r.status_code)

        # @todo test this
        # @todo maybe you really want to test zero-byte return pages?
        if r.status_code != 200 and not ignore_status_codes:
            # maybe check with content works?
            raise Non200ErrorCodeReceived(url=url, status_code=r.status_code, page_html=r.text)

        self.status_code = r.status_code
        if is_binary:
            # Binary files just return their checksum until we add something smarter
            self.content = hashlib.md5(r.content).hexdigest()
        else:
            self.content = r.text


        self.raw_content = r.content